The applicant's prior application US2004/0038714A1 (Rhodes), the disclosure of which is incorporated by reference, discloses an antenna system providing remote electrical beam adjustment for down tilt, beam width and azimuth.
Systems for effecting mechanical adjustment of antenna beam azimuth are known but have not been well integrated into a cellular antenna. Whilst Rhodes discloses integrated antenna systems providing electrical attribute adjustment (e.g. down tilt, azimuth and beam width) there is a need for an antenna providing good integration of mechanical and electrical attribute adjustment.
Further, electrical adjustment of azimuth without mechanical movement is possible using phase shifting of the various signals routed to the radiating elements. However, to do so, multiple columns of radiators are needed to produce a beam electrically moveable in azimuth without mechanical movement of the entire antenna or antenna backplane. For antennas having a single column of radiators, electrical azimuth adjustment is not feasible, and mechanical means must be used.
Single column antennas having electrical actuators, such as motors, are subject to very tight space and dimensional requirements, as the amount of room between the backplane and the radome and between the backplane and the enclosure and supporting structure is minimal. Accordingly, it is difficult to mount an electrical actuator, such as a motor and drive assembly within the space dictated by the antenna package.